Grain-to-Gain: Comparing the impact of wheat varieties and agricultural practices on sourdough microbiomes

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Commodities

• Agronomic: wheat

Practices

• Crop Production: food product quality/safety, varieties and cultivars
• Education and Training: extension, youth education
• Natural Resources/Environment: biodiversity
• Production Systems: organic agriculture
• Sustainable Communities: local and regional food systems

Wheat is a staple crop globally and one of the five most valuable crops in Pennsylvania. Wheat is milled into flour to produce staple foods like bread and baked products. Studies investigated the microbial diversity of wheat and bread products including sourdough. However, the changes of microbial diversity from wheat to flour to bread remains less understood. I propose to investigate the influence of wheat varieties, farming methods, and processing techniques in a sourdough model system. By tracking biodiversity changes from farm-to-fermentation, I seek to use this ancient knowledge to modernize wheat-based products.

Ancient and common wheat will be grown under organic or conventional farming. Amplicon sequencing of wheat berries will determine diversity and abundance of bacteria and fungi. Whole wheat and refined grain flours will be produced from the different wheat and farming methods. Flour from ancient v. modern wheat, organic v. conventional, and whole v. refined will be sequenced and utilized to create sourdough starters. Comparative physical and chemical analysis of starters will include organic acids, pH, and free amino acids. Mature sourdoughs will be sequenced. Outcomes from this study could provide insights into preservation and resilience of microbial communities from farm-to-fermentation.

This proposed work aligns with our current USDA NIFA funded project (#2023-67017-40251) that characterizes sourdough microbiomes to enhance quality and nutrition of breads. The proposed study seeks to conserve biodiversity in locally produced staple crops, including ancient wheat, which offers opportunities for market expansion. This research supports local farmers and consumers, promoting sustainable agriculture within Pennsylvania.

Objective 1: Compare microbial diversity between common wheat (T. aestivum) and ancient wheat (T. monococcum) farmed conventionally and organically in Pennsylvania. I hypothesize that ancient and common wheat will have significantly different microbial diversity. I also hypothesize that organically farmed grains will have higher alpha diversity. Overall, I hypothesize that ancient wheat grown organically will have the highest alpha diversity. Beta diversity is expected to be high between samples. This objective will result in tables with relative abundance of bacteria and fungi and results of statistical analyses of microbial diversity.

Objective 2:

(2a) Assess microbial diversity in whole-grain and refined grain flours derived from common wheat (T. aestivum) and ancient wheat (T. monococcum) farmed organically and conventionally in Pennsylvania.

(2b) Utilize flours from 2a to develop and characterize sourdough starter cultures and evaluate their functional outcomes. I hypothesize that whole wheat flour will have a higher alpha diversity than refined grain flour. I also hypothesize that ancient wheat grown organically and milled into whole wheat flour will produce sourdough starters with the lowest pH, highest organic acids, and highest microbial alpha diversity. Beta diversity is expected to be high between samples. This objective will result in tables with relative abundance of bacteria and fungi, statistical analyses of microbial diversity and proximate analysis measurements, and graphs illustrating sourdough proximate analysis results.